Cardinal In Pectore

It’s my understanding that when a Pope names new Cardinals, it is his option to name one in pectore, or in secret. He does not identify this person, among other reasons, for fear that that person’s life may be put at risk, such as being a priest in countries where Catholicism is banned. This person is not an “official” Cardinal until his name is made public.

I am under the impression that by the term “in public”, it does not necessarily mean that his name is announced. He could have written it down, entrusted it to someone with standing in the Church, told the other Cardinals under condition of secrecy, or something along those lines.

With the secrecy surrounding the upcoming conclave, would this Cardinal be, first, eligible to vote; secondly, able to attend the conclave while keeping his identity from the public? I would assume that the current College of Cardinals by now know of his identity, and that his vote would be accepted.

Am I on the mark with any of this?

From http://americamagazine.org/articles/consistory.htm

This topic came up a couple of days ago in Pope John Paul II’s cardinal seclections in pectore. At that time I linked to a Catholic Encyclopedia article that noted that In Pectore cardinals who are not made public before the death of the pope appear to be SOL, based on the opinions of Canon lawyers during the time of Pius X.

Of course, since it is a lawyerly matter, we now have a contrary opinion from Fr. James Conn (about 2/3 the way down the article) who speculates that as long as Pope John Paul II left a written record of his choice, the man could still get his red hat.
(I don’t know how long the article will be on-line. It is an AP release: search on “james conn pectore”.)

(There is, by the way, no limit on the number of cardinals who may be named in pectore.)